Apparatus and method for adjustment and coordination of circuit breaker trip curves through graphical manipulation

Abstract

The trip curves of circuit protection devices in an electric power distribution system are individually adjusted and coordinated in a hierarchy of protection devices by graphical manipulation, such as by dragging with a mouse, segments of the trip curves presented on a display device. The existing parameter settings can be provided to the display device and the adjusted parameter settings returned to the protection devices manually, but preferably, a communications network provides automatic transfer of the settings in both directions.

What is claimed is: 
     
       1. Apparatus for adjusting a trip curve defined by parameter settings for a protection device in an electric power distribution system, said apparatus comprising: display means;   means for generating a graphical display of said trip curve on said display means from said parameter settings;   adjusting means for graphically manipulating on said graphical display of said trip curve to adjust said trip curve and said parameter settings to generate an adjusted trip curve and adjusted parameter settings; and   means outputting said adjusted parameter settings defining said adjusted trip curve.   
     
     
       2. The apparatus of claim 1 wherein said adjusting means for graphically manipulating said graphical display of said trip curve comprises means for dragging said graphical display of said trip curve across said display means. 
     
     
       3. The apparatus of claim 2 wherein said trip curve comprises a plurality of segments and wherein said means for dragging said trip curve comprises means selecting a segment of said trip curve for dragging across said display means, and wherein said adjusting means further includes means adjusting other segments of said trip curve to accommodate for dragging of said selected segment. 
     
     
       4. The apparatus of claim 3 wherein said adjusting means comprises means limiting movement of said selected segment of said trip curve to limiting values for said parameter settings. 
     
     
       5. The apparatus of claim 4 wherein said parameter settings have discrete values and said adjusting means adjusts said adjusted parameter settings to a closest discrete parameter setting for the selected segment. 
     
     
       6. The apparatus of claim 4 wherein said trip curve has a sloped segment having a slope determined by a slope parameter setting, and wherein said adjusting means includes means for graphically manipulating said sloped segment to adjust said slope parameter setting. 
     
     
       7. The apparatus of claim 6 wherein said means for graphically manipulating said sloped segment to adjust the slope of the sloped segment comprises means graphically moving one end of said sloped segment while maintaining the other end of said sloped segment in a fixed position. 
     
     
       8. The apparatus of claim 1 adapted for coordinating trip curves for a plurality of said protection devices wherein said means for generating a graphical display generates a graphical display of each of said trip curves on said display means simultaneously and said adjusting means comprises means for graphically manipulating said graphical display of at least one of said trip curves to adjust said one trip curve and associated parameter settings to provide a margin (M) between said trip curves. 
     
     
       9. The apparatus of claim 8 wherein said means for manipulating said trip curve comprises means for dragging said at least one trip curve across said display means. 
     
     
       10. The apparatus of claim 9 wherein said trip curves comprise segments, and wherein said means for dragging comprise means for dragging one of said segments of said one trip curve. 
     
     
       11. Apparatus comprising: at least one protection device for an electric power distribution system having parameter settings defining a trip curve for said protection device:   means for adjusting said trip curve comprising: display means;   means generating a graphical display of said trip curve on said display means from said parameter settings; and   adjusting means for graphically manipulating on said graphical display of said trip curve to adjust said trip curve and said parameter settings to generate an adjusted trip curve and adjusted parameter settings; and     communication means for transferring said parameter settings from said protection device to said means for adjusting said trip curve and for retransferring said adjusted parameter settings to said protection device to provide said adjusted trip curve for said at least one protection device.   
     
     
       12. The apparatus of claim 11 including a plurality of protection devices each having parameter settings defining a trip curve, said means for generating a graphical display comprising means for simultaneously generating a graphical display for trip curves on said display means for at least two protection devices including said at least one protection device and another protection device, said adjusting means comprising means for graphically adjusting at least said trip curve of said one protection device relative to the trip curve for said another protection device to coordinate operations of said at least two protection devices; and said communication means comprising means transferring parameter settings of said at least two protection devices to said means for adjusting said trip curves and for retransferring at least said adjusted parameter settings back to said at least one protection device.   
     
     
       13. A method of coordinating trip curves defined by parameter settings of a plurality of protection devices in an electric power distribution system, said method comprising the steps of: storing stored values of said parameter settings of each of said trip curves;   generating as a display on a display device simultaneous graphical representations of at least two of said trip curves from said stored values of said parameter settings;   graphically manipulating said display of said graphical representation of at least one of said trip curves associated with at least one of said protection devices to an adjusted position to provide margins (M) between said trip curves;   updating said stored values of said parameter settings of said at least one of said trip curves to adjusted values produced by said adjusted position of said one trip curve; and   inserting said adjusted values of said parameter settings into said at least one of said protection devices.   
     
     
       14. The method of claim 13 wherein said graphical representations of said at least two of said trip curves comprise a series of line segments and said step of graphically manipulating comprises dragging one of said line segments on said display to said adjusted position. 
     
     
       15. The method of claim 14 wherein said inserting step comprises transmitting said adjusted values of said parameter settings to said at least one protection device over network communications. 
     
     
       16. The method of claim 15 wherein the step of storing comprises transmitting said parameter settings from said plurality of protection devices to storage means over said communications network.